Climate zones

Which climate zones occur in East Africa and why do they occur there?

In Africa six different climate zones occur. This is because the middel of africa lies around the equator so is very moist. But for example the Northern part is one big dessert. The six different climate zones are tropical wet, tropical summer rainfall, semiarid, arid, highland, and Mediterranean.

The tropical wet climate zone occurs mostly around the equator because around the equator it is very hot and moist.

Tropical summer rainfall occurs most around the north and south of the equator. This zone is defined by a dry period which lasts three to eight months.

Semiarid Surrounding the tropical summer rainfall zone are areas of semiarid and then arid climates in north central Africa, east central Africa, and southern Africa. The semiarid, or hot steppe, zone has a short rainy season of up to three months with about 250 to 500 mm (ten to twenty in) of rain per year.

arid : Is almost the same as amirid but it is a little bit dryer then amirid. So there it is more difficult to grow crops.

highland tropical highland climates are common in much of East Africa. Temperatures in the highlands of Ethiopia and Kenya average 16° to 21°C, on average about 5° C cooler than the lower plateau areas of Kenya, Uganda, and Tanzania.

Mediterranean The coastlands of the Cape region of South Africa and the North African coast from Morocco to Tunisia have Mediterranean climates. These areas have mild, rainy winters followed by a prolonged summer when conditions are warm and dry. They receive between 250 to 1,000 mm (10 to 40 in) of rainfall per year.

Why does East Africa have a dry and a wet season (with two reasons)

The wet season (also called the monsoon) appears for two reasons. but before I can explain I need to explain a different thing. Around the equator is is very hot and moist. Hot air always goes up. So the moist hot air goes up and forms clouds full of rain. This falls then down again in the rainforest. But because the air cools down it comes down. So the cold and rainless air goes down around 30 degrees from the equator away. So that is the reason you have dessert in North and South Africa.

The 2 reasons Africa has a wet and a dry season are: 1: Because from Indian Ocean hot and cold sea currents switch each other off an flow towards Africa. Cold air is very dry and…cold. Warm air contains a lot of rain and is …warm. So this causes the wet and dry season. The second reason is because the sun changes position. The further the sun is away from the equator the colder it is. This also the reason why we have seasons.

What is the relation between climate zones in the west of the United States?

In the west of the United states you have a lot of mountain ranges. When clouds have a lot of water in them they become heavier and flow lower. Sometimes when there is a mountain range with very high mountains the clouds are stopped. So the clouds cool down and let their rain fall for example in the Rocky mountains. This is also the reason why the midwest of U.S is so dry.

Give two examples of irrigation systems used in North-America and Africa.

Subsurface irrigation. Underground pipes or open ditches are blocked to back up ground water and force it up into a crop root zone. This method is primarily used in the Sacramento-San Joaquin River Delta.

Surface irrigation. This includes wild flood, border, basin, furrow irrigation without sprinklers, wheel-line sprinklers followed by furrow irrigation, and hand move sprinklers fol- lowed by furrow irrigation. Land that is irrigated initially with sprinklers and subsequently with furrows is included in this category.

How does irrigation cause salinisation?

Groundwater extraction and irrigation can increase salt concentrations in water and soils in several ways. First, irrigation increases the salinity of soil water when evaporation removes water but leaves salt behind. This occurs when irrigation water contains some salt and irrigation rates are not high enough to flush the salt away.